Click here to download the cards. There is red, yellow or turquoise set to match your classroom's color scheme! They are all on the same document.
In the beginning of the year (when I am still molding and shaping student behavior) I use a system I call "Compliment" (what can I say, I stink at creative names!). Very simple and easy but it gets the job done. Whenever I notice that the whole class (or the vast majority) is making the correct choice they earn a letter toward the word "compliment." They could earn a letter for hallway behavior, following a direction quickly, cleaning up quickly and quietly, being silent during a fire drill or being silent when an adult comes in to speak to me and so on. When students spell the entire word then they can vote (democracy and majority rules are third grade concepts) on a reward. I often list examples like Popsicles, extra recess, computer free time, etc. Then we vote as a class, majority rules. I warn the students of this before we even vote to make sure to avoid the "whines." I hate the "whines."
I used die cut stars with the letters on them but I made these super cute letters. I may have to print these myself..so much cuter than my stars. You can either magnetize the back and add the letters to the white board as they are earned or you could clip them on the white board backwards with magnetic clips. As students earn letters you can flip the next letter.
Another similar ( and way too cute) concept is the "brownie points" system which is super cute. You can read about this idea at here at First Grader at Last or here at What the Teacher Wants.